Researchers at Johns Hopkins University have created a low-cost 3D printed waterproof drone that can stay submerged in salt water for up to two months and launch into the air on command when needed. Known as the Corrosion Resistant Aerial Covert Unmanned Nautical System, or CRACUNS, this amphibious UAV can be used in high-risk intelligence gathering missions and is being further developed to be able to go back and forth between aerial and underwater environments.

Developed for use by the NAVY, the CRACUNS (a cheeky reference to the legendary Kraken sea monster) is a first-of-its-kind submersible UAV that can either be mounted to a submarine or fixed to an unmanned underwater vehicle (UUV), where it remains unseen yet ready-for-action. When needed, it uncouples from its base, floats to the surface, and can then take off into the skies.

In order to develop such a machine, researchers at John Hopkins University Applied Physics Laboratory in Laurel, Maryland, needed to design a drone that could both survive and operate at significant underwater depths without structural metal parts or machined surfaces, which would quickly succumb to corrosion. They thus turned to advanced additive manufacturing technology, provided by the fabrication experts at the Research and Exploratory Development Department. They designed a lightweight, submersible, composite airframe from custom 3D printed parts.

The most sensitive electric components were then sealed in a dry pressure vessel. Components that need to remain exposed, such as the four electric motors, were coated with a cheap and commercially available protective coating. In lab tests, the CRACUNS was left submerged in salt water for as long as two months without showing any signs of corrosion and was still able to fly just fine.

According to the APL team, the CRACUNS enables new capabilities not possible with existing UAV or UUV platforms. Its ability to operate in harsh shore environments, as well as its payload flexibility, enables a wide array of potential missions.

Furthermore, because of its 3D printed parts and use of off-the-shelf coating, the CRACUNS waterproof drone is quite cheap to produce, and could be produced in large numbers or used as a disposable tool during high-risk operations. For non-military use, the CRACUNS could also serve research institutions as a low-cost drone to monitor the seas.

“CRACUNS successfully demonstrated a new way of thinking about the fabrication and use of unmanned systems,” said APL’s Rich Hooks, an aerospace and mechanical engineer who developed the novel additive manufacturing techniques used on CRACUNS.

The CRACUNS 3D printed waterproof drone is still in its prototype stage, however it already shows great promise. Currently, it can only launch from underwater into the skies, however the APL team’s next step is to further improve its structure and find a way of allowing the CRACUNS re-enter the water after its aerial mission is complete.